Our systems are very adaptive, sooner or later the honey moon period will fade, no matter how stretched it is, and you'll simply require more or more frequent usage... One other thing to note about nicotine itself regarding our development of tolerance - that process is very dependable on memorial cues since how much this "drug" effects brain's higher cognitive functioning (it's still fascinating to me how so many people with schizo disorders more or less unwittingly treat some of their negative symptoms severity by smoking, and as some studies show that actually puts a bit of a dent there...). Anyway, about alternatives: nicotine itself is a powerful nicotinic acetylcholine receptor agonist, actually more potent at binding to those receptors than our endogenous neurotransmitter acetylcholine, while of course the same might not be said about its main and long lasting metabolite cotinine. Having said that, and considering that there's nothing really much like it out there to use or substitute with, you could look into some supplemental AchEIs perhaps, like huperzine-a. If anything, it would provide some boost, while higher doses may make its accumulations in the system significant enough regarding nAch and NMDA antag profile to facilitate some noradrenergic activations/modulations that are more visibly seen with nicotine use (meaning not the same, but may be similar to some extent)...